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Spamlet Spamlet is offline
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Default Two-way and intermediate switches


"Tim Watts" wrote in message
...
John
wibbled on Wednesday 30 June 2010 20:37

I'm no electrician but my mate reckons that you can have as many
intermediate switches as you want on a two-way circuit (think switching
the landing light on downstairs before going to bed but it's a long
landing with six rooms - he wants each room to have its own switch on the
landing).

I reckon that you can have the two two-way switches as normal, with one
intermediate switch. Who's correct - and if he's right, and you can have
more than one intermediate switch, can anyone give a wiring diagram
(preferably not ASCII as I can never make head nor tail of them)?

Cheers and TIA


You can have zero or more intermediate switches.

Think about it:

Normal 2-way means that you send voltage either wire A or wire B. The lamp
lights if both switches are set to both Wire A *or* both wire B.

The intermediate switch is a funky little beast (that doesn't exist in any
normal equipment switch range say in Maplin or RS) that swaps wire A and B
over.


There is a diagram of the internal switch wiring he
http://en.wikipedia.org/wiki/Switch had my brain aching a bit till I saw
it.

S


Each time you swap A and B you change the state of the lamp, but the end
switches can still also change the state of the lamp.

You can therefore have as many swappers (int switches) as you like,
subject
to resistance constraints.

Cheers

Tim
--
Tim Watts

Managers, politicians and environmentalists: Nature's carbon buffer.